Sounds like the problem here is going to be in the Stop Lamp Switch. It's mounted to the top of the Brake Pedal Assembly, under the driver's side dash (click here for an image). Inspect the electrical connector and wire harness for any loose, broken or damaged wires. Inspect the switch mount and contact points for any broken or misaligned parts. If the visual inspection checks ok, more than likely, the internal plunger has failed and the switch will need to be replaced. Please do the right thing and remember to leave a rating using the rating system at the top of this page or accept the answer so I may be credited for this Q&A. You can ask follow-up questions any time, even after you rate or accept. Remember, your rating is required.